1. Field of the Invention
This invention relates to an anti-inflammatory or anti-sunburn cosmetic composition.
2. Description of the Prior Art
It is well known that the sunlight and/or lights by artificial light sources, in particular, ultraviolet rays have some influences on the skin. Lights are classified, depending on the wavelengths, into ultraviolet rays (200-400 nm), visible rays having longer wavelengths (400-700 nm) and infrared rays having further longer wavelengths (700 or more nm).
The ultraviolet rays in the shortest wavelength range (200-290 nm) is called "UV-C" and the light having this wavelength range in the sunlight is almost absorbed in the ozone zone, so that it does not reach the earth. However, a quartz mercury lamp radiates a light of the shortest wavelength 185 nm and a sterilizing ray of 253.7 nm and furthermore, UV-C is also radiated from other sources, e.g. discharge tubes of hydrogen or nitrogen, nuclear reactors, etc. This light causes erythema with a dose of 5 to 20 mmJ/cm.sup.2.
The ultraviolet rays in the middle wavelength range (290-320 nm) is called "UV-B" which causes erythema, bleb, sunburn upon irradiation for 4 to 20 hours. This wavelength range, generally promoting formation of melanin and causing pigmentation (sunburn) and skin injure, is present in the sunlight, whereby injure of the skin is maximized. An artificial sunlight generally has a wavelength of 320 to 400 nm.
The ultraviolet rays in the longer wavelength range (320-400 nm) is called "UV-A" having an energy of about 20 to 50 mmJ/cm.sup.2 and it is considered that this wavelength range instantaneously affects the skin, but does not cause a large change thereon.
However, it has lately been found with the progress of electron microscopes and skin histochemistry that the radiation of UV-B or UV-C tends to not only cause superficially chloasma or melanotic freckle but also reach the derma of the skin and bring on a slightly chronic change in the elastic fibers in the vascular wall or connective tissue, resulting in promotion of degeneration of the interior tissue, promotion of ageing of the skin and cause of cutaneous cancer. Further, it is found that such a phenomenon is proportional to the product of a light energy and radiation time (active energy density) and that UV-A promotes degeneration of the skin by UV-B described above, resulting in a cause of occurrence of cutaneous cancer. Therefore, the protection from this UV-A has become a great problem.
As described above, the so-called anti-inflammatory cosmetic composition comprising a UV shielding agent or UV absorber has been proposed for the purpose of protecting the skin from degeneration by lights, in particular, ultraviolet rays.
As known UV absorbing compounds, there are benzophenone derivatives (Japanese Patent Laid-Open Publication Nos. 108804/1987 and 139158/1988), kojic acid and its derivatives (Japanese Patent Laid-Open Publication No. 188609/1988), esterified compounds of vitamine C (Japanese Patent Laid-Open Publication No. 129212/1987), cinnamic acid derivatives and aminobenzoic acid derivatives (Japanese Patent Publication No. 31021/1977, Japanese Patent Laid-Open Publication Nos. 31023/1977, 35941/1984, 265215/1987 and 231637/1985), dibenzoylmethane derivatives (Japanese Patent Publication No. 6526/1988 and Japanese Patent Laid-Open Publication No. 24061/1987), ethylrutin derivatives (Japanese Patent Laid-Open Publication Nos. 146810/1988) and chalcone derivatives and flavone derivatives (Japanese Patent Laid-Open Publication Nos. 109544/1987 and 96120/1988).
As the light shielding agent, there are used benzophthalides (Japanese Patent Publication Nos. 42167/1983 and 15885/1984) and cosmetic compositions comprising hydrophobic titanium oxide powder in an oily cosmetic base (Japanese Patent Publication Nos. 42167/1983 and 15885/1984).
As a composite cosmetic, there are proposed a composition comprising a UV absorber (benzophenone type, aminobenzoic acid type, salicylate type and vitamine C) added to a sponge-like porous material such as ethylene-vinyl acetate copolymer or polyethylene (Japanese Patent Publication No. 51931/1987), a cosmetic comprising a UV absorber adsorbed on a porous material such as polystyrene and microcapsulated (Japanese Patent Publication No. 31932/1978), an anti-inflammatory composition comprising a UV absorber, fatty acid, amine base and acrylic polymer (Japanese Patent Publication No. 45607/1986), a cosmetic comprising an antioxidant, benzophenone UV absorber and unsaturated oils and fats and a cosmetic comprising urocanic acid and Parsole A (commercial name).
The synthetic compounds of the prior art used as a UV absorber have the problems that the addition quantity to a cosmetic basis is restricted by the solubility in oils, fats and aqueous bases, they have stimulus to the skin, they are deteriorated after absorbing UV to cause change of the UV absorbing capacity with the passage of time and coloration, they are not suitable for use as a cosmetic basis from the sanitary point of view and they have a limitation on the effect of absorbing light.
Titanium oxide, zinc white and iron oxide, as a light shielding agent, in particular, finely divided products or surface-activated products thereof do not absorb ultraviolet rays, nor meet with change of the materials themselves with the passage of time and have little stimulus on the skin. When using the shielding agents capable of shielding visible rays and having a large hiding power, as a cosmetic, they tend to be whitened or excessively colored during use, so that the transparent feeling of the skin is deteriorated. Therefore, the amount thereof to be used is restricted in not only basic cosmetics but also foundation cosmetics, and the shielding agent in a suitable amount for beauty effect does not have a sufficient shielding effect of ultraviolet rays.
Furthermore, the cosmetics of the prior art have only a small absorbing and shielding effect for UV-A having lately been considered as an important problem.